the effects of fermacto, bactocell and biostrong in antibiotic-free diets on the performance of broilers

The aim of this study was to compare the effects of three antibiotic alternatives with a control (antibiotic-free) and an antibiotic diet on performance and gut morphology of broilers reared on litter. 600 day-old ross-308 chicks were assigned to 48 pens in a crd design with 6 × 2 factorial arrangements, in which 2 levels of chick density (5 and 7.5 chicks/m2) and 6 experimental diets (control, virginiamycin, fermacto, bactocell, biostrong and biostrong matrix-value formulated or biostrong-mv) were used. higher chick density increased starter feed intake and decreased grower feed conversion ratio (fcr) significantly (p<0.05). average daily gains (adg) were not different among experimental diets except biostrong-mv that was the least. fcr of different diets were equal, both in starter and grower period. performance traits didn't influenced by diet × density interaction. relative weight of digestive organs, especially jejunum, in antibiotic diets were lesser than other diets (p<0.05). the length per gram of jejunum resulted from experimental diets were similar, and so for ileum except that of fermacto that was significantly lesser than biostrong (p<0.05). the result of current experiment (winter and corn-soybean based diets) had shown that antibiotic alternatives not only didn’t have an effect similar to antibiotic but also to control diet. furthermore matrix-value method of diet formulation with biostrong lessened chick performance.